OBJECTIVES To compare predictors of hospitalization and death in nursing home residents with pneumonia and other lower respiratory infections (LRIs). DESIGN A nested cohort study. SETTING Nine nursing homes in southern Ontario. PARTICIPANTS Three hundred fifty-three nursing home residents with LRIs (enrolled in the control arm of a clinical trial). MEASUREMENTS Comorbidities, vaccination status, age, health-related quality of life, functional status, and vital statistics were evaluated as potential predictors of hospitalization and mortality at 30 days. RESULTS Moderate to high disease severity score on a practical severity scale was a strong independent predictor of hospitalization (odds ratio (OR)=7.12, P<.001) and mortality (OR=5.04, P=.003). Diagnosis of pneumonia, established using chest radiograph, was also associated with hospitalization (OR=2.43, P=.008) and mortality (OR=2.35, P=.02). Oxygen saturation (<90%) was a strong independent predictor of hospitalization (OR=3.02, P=.004) but was not a significant predictor of mortality in multivariable analyses. Diagnosis of congestive heart failure (OR=2.26, P=.02) was an independent predictor of hospitalization, whereas receipt of pneumococcal vaccine (OR=0.36, P=.01) and greater functional independence (OR=0.92, P=.02) were negatively associated with hospitalization. CONCLUSION In nursing home residents with LRI, severity of illness and radiographically confirmed pneumonia are predictive of death and hospitalization.